Safety device for elevators.



A. MUELLER.

SAFETY DEVICE FOR ELEVATORS.

APPLICATION mu) mma. 1915.

1,163,165. Patented Dec. 7, 1915.

ARTHUR MUELLER, OF iv'Ew YORK, N. Y.

SAFETY DEVICE FOR ELEVATORS.

Specification of Letters Patent.

Patented Dec. 7, 1915.

Application filed January 28, 1915. Serial N 0. 4,817.

To all whom it may concern.

Be it known that I, ARTHUR MUELLER, a citizen of the United States of America, and a. resident of the borough of Brooklyn, county of Kings, city and State of New York, have invented certain new and useful Improvements in Safety Devices for Elevators, of which the following is a specification accompanied by drawings.

This invention relates to safety devices for elevators and the object of the invention is to prevent accidents in case the cable becomes slack or does not wind up properly on the drum, or in case there is a broken strand of the cable, which may cause a tangle.

If the cable of an elevator does not wind properly on. the drum, and one or more of the convolutions ride up on top of the others, excessive wear occurs and even a new cable may wear out in a comparatively short time and become so weakened as to cause an accident. Accidents also may occur in case a strand of the cable becomes broken.

In accordance with my invention, an electric safety device is provided which automatically stops the motor in case the cable is not winding properly or in the case of a broken strand. The stoppage of the motor and car serves to indicate to the operator that there is a defect in the cable, which under ordinary circumstances might not be noticed until the damage was beyondrepair.

My device is simple and cheap to con struct, will safeguard persons using an elevator and will save time and money to the owner ofbuildings in which elevators are installed. The device will act so quickly that a defect in the cable or mechanism will be detected before any great damage can be one.

The apparatus is illustrated in the accompanying drawing, which is a diagrammatical representation of a winding drum and the safety device set up in connection therewith.

Referring to the drawings, A represents a winding drum of the usual character, which may be of metal provided with the spiral grooves B in which the cable C, which may be constructed of metal strands, is wound. The drum is mounted in any suitable or usual manner on the shaft D, carried in bearings in the standards E.

The drum shaft D is adapted to be operated by the usual electric motor or other source of power and F and G represent the electric mains furnishing power to the motor (not shown).

In accordance with this invention I arrange a safety contact device in proximity to' the drum A and extending longitudinally along said drum. This device is shown in one of its preferred forms as a flexible metal strip, wire or bar H arranged in such position, as indicated in the drawing, that a very slight derangement of the cable on the drum will cause contact to be made between the cable and the safety contact device H. Furthermore a loose or broken strand of the cable will make contact with the safety contact device H. An electro-responsive controlling device is provided for controlling the circuit of the elevator motor, and as shown this electro-responsive device consists of the magnets J controlling the armature Kin the form of a lever pivoted at L on the standard 0. The electro-responsive device may take any convenient form and I have simply illustrated a suitable magnetic switch. One leg P of the lever K is pressed by a retracting spring Q, which may be adjusted as by means of the thumb screw It, to maintain the lever K normally away from the magnets J when said magnets are deenergized. A suitable switch in the form of a knife blade switch S is connected in circuit with the mains F and G and bears against a spring T, which causes the switch to open when the finger U is released from the pivoted latch V. The depending end W of the lever K is adapted to throw the latch V and release the switch S when the magnets J are energized.

Any suitable source of current may be provided for the magnets J, as for instance, the battery, and circuit connections Y are made between the frame E of the winding drum and the magnets J, and other connections Z are made between the safety contact device H and the battery X and magnets.

In the operation of the apparatus, in case the cable 0 winds up on the drum or in case there is a broken strand, contact is made between the cable and the safety contact device H. The circuit is completed from the battery X through the magnets and through the frame E and drum and cable to the contact device H and back to the battery. The magnets J are energized, the lever B is drawn down and the latch V is tripped, which releases the switch S. and the circuit the motor is broken. The car is thus automatically stopped and the cable may be examined to determine the cause of the stoppage.

One of the great advantages of my apparatus resides in the fact that a small difiiculty with the cable may be detected before the derangement becomes greater, and a very light contact between the cable or any portion thereof and the safety contact device H will serve to complete the electric circuit through the magnets J which in turn releases the switch S. The relay apparatus connected with the battery X is depended upon to do the actual work of opening the motor circuit and the apparatus has been found to be positive in action and highly efficient in actual practice.

I claim and desire to obtain by Letters Patent the following:

1. In a. safety device for elevators, the combination with the winding drum and cable, of a safety contact device arranged in proximity to said drum, so that derangement of the convolutions of the cable on the drum, or a broken cable Strand, will cause contact to be made with said safety contact device, an electro-responsive controlling device for controlling the circuit of the elevator motor, and circuits and connections including said controlling device, the drum and cable and said safety contact device, whereby contact between the cable and said safety contact will energize the electroresponsive device and stop the elevator motor.

2. In a safety device for elevators, the combination with the winding drum and cable, of a safety contact device in the form of a flexible bar or strip arranged in proximity to the drum and extending longitudinally of the drum, so that derangement of the convolutions of the cable on the drum, or a broken cable strand, will cause contact to be made with said safety contact device, an electro-responsive cont-rolling device for con trolling the circuit of the elevator motor, and circuits and connections including said controlling device, the drum and cable and said safety contact device, whereby contact between the cable and said safety contact will energize the electro-responsive device and stop the elevator motor.

3. In a safety device for elevators, the combination with the winding drum and cable, of a safety contact device in the form of a flexible bar or strip arranged in proximity to the drum and extending longitudinally of the drum, so that derangement of the convolutions of the cable on the drum, or a broken cable strand, will cause contact to be made with said safety contact device, an electro-responsive controlling device for controlling the circuit of the elevator motor, circuit connections between the electroresponsive device and the frame of the drum, circuit connections between the electroresponsive device and the said safety contact device, and a switch in the motor circuit connected to be operated by said electro-responsive device.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

ARTHUR MUELLER.

Witnesses ANNA PINCUS, EMIL KIRRMANN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. G. 

